[callefoss]

I just bougt an extra 160Gb HD for my PowerMac and then wanted to get rid of the second partition on my first HD, without using any partition software. So I decided to use the Restore function in Disk utility:

1. I booted from a cd.
2. Launched Disk Utility, and made an image of my primary partition with all the system data.
3. Saved it on my new physical HD.
4. Erased the partitions on my first HD in Disk Utility.
5. Put back the image.

Everything worked fine except that now I could not boot. The files were there back on the HD but something obviously went wrong here.

Any ideas?

Thanks

[CharlesS]

When you restored the image back onto the hard drive, did you make sure to click the "Erase Disk" check box? Doing so will do a block copy, which will automatically get the blessed folders, etc. Otherwise it just does a file copy, and you might have to re-bless the CoreServices folder manually. If this is the case, you can do it like this, but you'll have to use the Terminal:

sudo bless -folder "/Volumes/<hard disk name>/System/Library/CoreServices" -bootinfo "/Volumes/<hard disk name>/usr/standalone/ppc/bootx.bootinfo"

[callefoss]

Thanks, did it again and this time like you said, and it worked.

Cheers

[Simon]

Originally posted by CharlesS:
When you restored the image back onto the hard drive, did you make sure to click the "Erase Disk" check box? Doing so will do a block copy, which will automatically get the blessed folders, etc. Otherwise it just does a file copy, and you might have to re-bless the CoreServices folder manually.

Charles, is this a problem just because the source is a disk image?

I do backups to a FW disk and never use the erase box (because the partitions are usually just newly created when I backup), but the FW partition with the copy of my main partition is always bootable, regardless of the erase box setting. Does that make sense?

[CharlesS]

Originally posted by Simon:
Charles, is this a problem just because the source is a disk image?

I do backups to a FW disk and never use the erase box (because the partitions are usually just newly created when I backup), but the FW partition with the copy of my main partition is always bootable, regardless of the erase box setting. Does that make sense?

This is what the man page for asr (which Disk Utility is using, under the hood) says:

HOW TO GET THE FASTEST RESTORES
If you are trying to understand file copy (slower) vs. block copy (fast):
When you see "Restoring...", that means the source image volume is larger
than the target volume or the volume geometry of the source image is
stretchable to the target size, allowing a high speed block copy to
occur. As of asr in OS X 10.3, the geometry restrictions have been sig-
nificantly relaxed such that stretchable source images are no longer
required.

When you see:
Copying "/private/tmp/..." (/dev/diskMsN) to "<target>" (/dev/diskPsQ)...
It means the above is not true, and asr has fallen back to a file copy
operation. asr will only block copy if the volume geometries support it
AND you are doing an erase restore. If you are restoring in place, a
file copy is always performed.

I've done restores both ways, both with the erase box checked (block copy) and with it unchecked (file copy) and can confirm that the block copy is much faster, like the man page says. However, the real benefit in my mind is that the block copy results in a disk that is much more exactly like the original. Since the blocks themselves are copied, any other stuff on the disk, such as the information about where the blessed system folder is, gets copied as well, whereas with a file copy all it does is copy the files over, which isn't much different than just using the ditto tool or Carbon Copy Cloner or something. With a file copy, you have to explicitly bless the system folder afterward, which asr may or may not do - I'm not sure, since I don't think the source to asr is available - but in my experience, it seems like it doesn't, since the disks I imaged using the file copy method ended up not being bootable and required me to bless them manually (using the command I posted above). So either it doesn't bless, or it doesn't consistently bless and sometimes either screws up or just doesn't bless when coming from a disk image. I don't know. Whatever the reason is, I just find it far, far preferable just to check the "Erase Disk" check box when imaging a disk, because then you know everything is going to Just Work™.

[Simon]

That's very interesting. I'm not quite sure anymore if it said "Restoring..." or "Copying...", but I'll check next time.

What I'm sure of is that I got blessed partitions w/o having to check the erase box. After backing up to my FW HD partition I can open System Preferences and check the backed up partition as startup volume. When I restart the Mac then boots from the FW partition, so I guess the partition must have retained the blessing somehow.

Thanks for sharing your insight.